U.S. patent number 11,203,251 [Application Number 16/084,677] was granted by the patent office on 2021-12-21 for vehicle air conditioning device.
This patent grant is currently assigned to SANDEN AUTOMOTIVE CLIMATE SYSTEMS CORPORATION. The grantee listed for this patent is SANDEN AUTOMOTIVE CLIMATE SYSTEMS CORPORATION. Invention is credited to Tetsuya Ishizeki, Ryo Miyakoshi, Kohei Yamashita.
United States Patent |
11,203,251 |
Ishizeki , et al. |
December 21, 2021 |
Vehicle air conditioning device
Abstract
There is disclosed a vehicle air conditioning device which
inhibits generation of noise in a solenoid valve 30 disposed on an
inlet side of a radiator 4 and improves durability of the solenoid
valve. A second operation mode is executed to shut off an outdoor
expansion valve 6, close the solenoid valve 30, open a solenoid
valve 40 and thereby send a refrigerant discharged from a
compressor 2 through a bypass pipe 35 to an outdoor heat exchanger
7. When a first operation mode to open the solenoid valve 30 and
close the solenoid valve 40 and thereby send the refrigerant to the
radiator 4 is shifted to the second operation mode, a controller
opens the solenoid valve 30 at a timing to stop the compressor
2.
Inventors: |
Ishizeki; Tetsuya (Isesaki,
JP), Yamashita; Kohei (Isesaki, JP),
Miyakoshi; Ryo (Isesaki, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
SANDEN AUTOMOTIVE CLIMATE SYSTEMS CORPORATION |
Isesaki |
N/A |
JP |
|
|
Assignee: |
SANDEN AUTOMOTIVE CLIMATE SYSTEMS
CORPORATION (Gunma, JP)
|
Family
ID: |
1000006004710 |
Appl.
No.: |
16/084,677 |
Filed: |
April 5, 2017 |
PCT
Filed: |
April 05, 2017 |
PCT No.: |
PCT/JP2017/014887 |
371(c)(1),(2),(4) Date: |
September 13, 2018 |
PCT
Pub. No.: |
WO2017/179594 |
PCT
Pub. Date: |
October 19, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190070933 A1 |
Mar 7, 2019 |
|
Foreign Application Priority Data
|
|
|
|
|
Apr 14, 2016 [JP] |
|
|
JP2016-081242 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60H
1/22 (20130101); F25B 1/00 (20130101); B60H
1/3213 (20130101); B60H 1/2225 (20130101); B60H
1/32 (20130101); B60H 1/3202 (20130101); F25B
39/04 (20130101); F24F 2110/12 (20180101) |
Current International
Class: |
B60H
1/00 (20060101); F25B 1/00 (20060101); B60H
1/22 (20060101); B60H 1/32 (20060101); F25B
39/04 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
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|
|
1952528 |
|
Apr 2007 |
|
CN |
|
103786547 |
|
May 2014 |
|
CN |
|
2727754 |
|
May 2014 |
|
EP |
|
H08282262 |
|
Oct 1996 |
|
JP |
|
2001-260645 |
|
Sep 2001 |
|
JP |
|
2002-106978 |
|
Apr 2002 |
|
JP |
|
2004-216934 |
|
Aug 2004 |
|
JP |
|
2005-514253 |
|
May 2005 |
|
JP |
|
2013-23210 |
|
Feb 2013 |
|
JP |
|
2013-522116 |
|
Jun 2013 |
|
JP |
|
2016049837 |
|
Apr 2016 |
|
JP |
|
Other References
Atsuo, Air Conditioner for Vehicle, 1996, Full Document (Year:
1996). cited by examiner .
Office Action dated Jan. 22, 2021 issued in Chinese Patent
Application No. 201780018150.7. cited by applicant.
|
Primary Examiner: Martin; Elizabeth J
Assistant Examiner: Babaa; Nael N
Attorney, Agent or Firm: Cozen O'Connor
Claims
The invention claimed is:
1. A vehicle air conditioning device comprising: a compressor to
compress a refrigerant, an air flow passage through which air to be
supplied to a vehicle interior flows, a radiator to let the
refrigerant radiate heat, thereby heating the air to be supplied
from the air flow passage to the vehicle interior, a heat absorber
to let the refrigerant absorb heat, thereby cooling the air to be
supplied from the air flow passage to the vehicle interior, an
outdoor heat exchanger disposed outside the vehicle interior, an
outdoor expansion valve to decompress the refrigerant flowing out
from the radiator and flowing into the outdoor heat exchanger, a
first opening/closing valve disposed between a discharge side of
the compressor and an inlet side of the radiator, a bypass pipe
which branches on an upstream side of the first opening/closing
valve and bypasses the radiator and the outdoor expansion valve to
send, to the outdoor heat exchanger, the refrigerant discharged
from the compressor, a second opening/closing valve disposed in the
bypass pipe, and a control device, so that the control device
switches between and executes a first operation mode to open the
first opening/closing valve, close the second opening/closing
valve, thereby send the refrigerant discharged from the compressor
to the radiator, and send the refrigerant flowing out from the
radiator through the outdoor expansion valve to the outdoor heat
exchanger, and a second operation mode to shut off the outdoor
expansion valve, close the first opening/closing valve, open the
second opening/closing valve, thereby send the refrigerant
discharged from the compressor through the bypass pipe to the
outdoor heat exchanger, and send the refrigerant flowing out from
the outdoor heat exchanger to the heat absorber, wherein in the
second operation mode, the control device controls the number of
revolutions of the compressor, including stopping, and wherein in
the state after the first operation mode is shifted to the second
operation mode, the control device opens the first opening/closing
valve at a timing to stop the compressor.
2. The vehicle air conditioning device according to claim 1,
wherein the control device limits the number of times that the
first opening/closing valve is opened at a timing to stop the
compressor to a predetermined number of times.
3. The vehicle air conditioning device according to claim 1,
comprising: an auxiliary heating device to heat the air to be
supplied from the air flow passage to the vehicle interior, wherein
the first operation mode includes any one, any combination or all
of: a heating mode to let the refrigerant discharged from the
compressor radiate heat in the radiator, decompress the refrigerant
from which the heat has been radiated, through the outdoor
expansion valve, and then let the refrigerant absorb heat in the
outdoor heat exchanger, a dehumidifying and cooling mode to send
the refrigerant discharged from the compressor through the radiator
to the outdoor heat exchanger, let the refrigerant radiate heat in
the radiator and the outdoor heat exchanger, decompress the
refrigerant from which the heat has been radiated, and then let the
refrigerant absorb heat in the heat absorber, and a cooling mode to
send the refrigerant discharged from the compressor through the
radiator to the outdoor heat exchanger, let the refrigerant radiate
heat in the outdoor heat exchanger, decompress the refrigerant from
which the heat has been radiated, and then let the refrigerant
absorb heat in the heat absorber, and the second operation mode
includes either one or all of: a dehumidifying and heating mode to
send the refrigerant discharged from the compressor through the
bypass pipe to the outdoor heat exchanger, let the refrigerant
radiate heat, decompress the refrigerant from which the heat has
been radiated, let the refrigerant absorb heat in the heat
absorber, and generate heat in the auxiliary heating device, and a
maximum cooling mode to send the refrigerant discharged from the
compressor through the bypass pipe to the outdoor heat exchanger,
let the refrigerant radiate heat, decompress the refrigerant from
which the heat has been radiated, and then let the refrigerant
absorb heat in the heat absorber.
4. The vehicle air conditioning device according to claim 3,
wherein the first operation mode is the heating mode or the
dehumidifying and cooling mode, and the second operation mode is
the dehumidifying and heating mode.
5. The vehicle air conditioning device according to claim 2,
comprising: an auxiliary heating device to heat the air to be
supplied from the air flow passage to the vehicle interior, wherein
the first operation mode includes any one, any combination or all
of: a heating mode to let the refrigerant discharged from the
compressor radiate heat in the radiator, decompress the refrigerant
from which the heat has been radiated, through the outdoor
expansion valve, and then let the refrigerant absorb heat in the
outdoor heat exchanger, a dehumidifying and cooling mode to send
the refrigerant discharged from the compressor through the radiator
to the outdoor heat exchanger, let the refrigerant radiate heat in
the radiator and the outdoor heat exchanger, decompress the
refrigerant from which the heat has been radiated, and then let the
refrigerant absorb heat in the heat absorber, and a cooling mode to
send the refrigerant discharged from the compressor through the
radiator to the outdoor heat exchanger, let the refrigerant radiate
heat in the outdoor heat exchanger, decompress the refrigerant from
which the heat has been radiated, and then let the refrigerant
absorb heat in the heat absorber, and the second operation mode
includes either one or all of: a dehumidifying and heating mode to
send the refrigerant discharged from the compressor through the
bypass pipe to the outdoor heat exchanger, let the refrigerant
radiate heat, decompress the refrigerant from which the heat has
been radiated, let the refrigerant absorb heat in the heat
absorber, and generate heat in the auxiliary heating device, and a
maximum cooling mode to send the refrigerant discharged from the
compressor through the bypass pipe to the outdoor heat exchanger,
let the refrigerant radiate heat, decompress the refrigerant from
which the heat has been radiated, and then let the refrigerant
absorb heat in the heat absorber.
6. The vehicle air conditioning device according to claim 5,
wherein the first operation mode is the heating mode or the
dehumidifying and cooling mode, and the second operation mode is
the dehumidifying and heating mode.
Description
TECHNICAL FIELD
The present invention relates to an air conditioning device of a
heat pump system which conditions air of a vehicle interior, and
more particularly, it relates to an air conditioning device which
is applicable to a hybrid car and an electric vehicle.
BACKGROUND ART
To cope with enhancement of environmental problems in recent years,
hybrid cars and electric vehicles have spread. Furthermore, as an
air conditioning device which is applicable to such a vehicle,
there has been developed a device including a compressor to
compress and discharge a refrigerant, an internal condenser
disposed on the side of a vehicle interior to let the refrigerant
radiate heat, an evaporator disposed on the side of the vehicle
interior to let the refrigerant absorb heat, an external condenser
disposed outside the vehicle interior to let the refrigerant
radiate or absorb heat, a first expansion valve to expand the
refrigerant flowing into this external condenser, a second
expansion valve to expand the refrigerant flowing into the
evaporator, a pipe which bypasses the internal condenser and the
first expansion valve, and a first valve to switch so that the
refrigerant discharged from the compressor flows through the
internal condenser or so that the refrigerant bypasses this
internal condenser and the first expansion valve to directly flow
from the pipe to the external condenser, and there are changed and
executed a heating mode to send the refrigerant discharged from the
compressor to the internal condenser through the first valve,
thereby let the refrigerant radiate heat, decompress the
refrigerant from which the heat has been radiated through the first
expansion valve and then let the refrigerant absorb heat in the
external condenser, a dehumidifying mode to let the refrigerant
discharged from the compressor radiate heat in the internal
condenser through the first valve, decompress the refrigerant from
which the heat has been radiated through the second expansion valve
and then let the refrigerant absorb heat in the evaporator, and a
cooling mode to send, to the external condenser, the refrigerant
discharged from the compressor and bypassing the internal condenser
and the first expansion valve through the first valve, let the
refrigerant radiate heat in the external condenser, decompress the
refrigerant through the second expansion valve and then let the
refrigerant absorb heat in the evaporator (e.g., see Patent
Document 1).
CITATION LIST
Patent Documents
Patent Document 1: Japanese Patent Application Publication No.
2013-23210
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
As described above, in Patent Document 1, there is a situation
where a refrigerant does not flow through an internal condenser
(corresponding to a radiator in the present application) when a
mode changes to a cooling mode. That is, an outlet of a first valve
on the side of the internal condenser is closed. This closing
results in a state where the refrigerant is confined within a
closed circuit including an internal condenser (107) and extending
from a first valve (117) to a first expansion valve (119).
Therefore, when a compressor is stopped immediately after the mode
is changed to the cooling mode, a pressure on the side of the
internal condenser might be higher than a pressure on a discharge
side of the compressor.
Here, when a flow channel is changed with two opening/closing
valves, i.e., the opening/closing valve (a first opening/closing
valve in this application) on the side of the internal condenser
(the radiator in the present application) and the opening/closing
valve (a second opening/closing valve) on the side of an external
condenser (an outdoor heat exchanger in the present application) in
place of the first valve that is a three-way valve, the pressure on
the internal condenser side (a radiator side) becomes higher than
the pressure on the discharge side of the compressor (a compressor
in the present application) during the stop thereof, and a reverse
pressure may be then applied to the opening/closing valve (the
first opening/closing valve in the present application) on the
internal condenser side, thereby causing hunting. Furthermore, when
the hunting occurs in the opening/closing valves, there are
problems that noise is generated in the opening/closing valves and
that their durability deteriorates.
The present invention has been developed to solve such conventional
technical problems, and an object thereof is to provide a vehicle
air conditioning device which is capable of inhibiting generation
of noise in a first opening/closing valve disposed on an inlet side
of a radiator and improving durability of the opening/closing
valve.
Means for Solving the Problems
A vehicle air conditioning device of the invention of claim 1
includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in the bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber, and the vehicle air conditioning device is
characterized in that after the first operation mode is shifted to
the second operation mode, the control device opens the first
opening/closing valve at a timing to stop the compressor.
The vehicle air conditioning device of the invention of claim 2 is
characterized in that in the above invention, the number of times
to open the first opening/closing valve by the control device is
limited.
A vehicle air conditioning device of the invention of claim 3
includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in the bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber, and the vehicle air conditioning device is
characterized in that when shifting from the first operation mode
to the second operation mode, the control device stops the
compressor prior to execution of control to each of the closing of
the first opening/closing valve, the opening of the second
opening/closing valve and the shutoff of the outdoor expansion
valve, then closes the first opening/closing valve, opens the
second opening/closing valve, shuts off the outdoor expansion
valve, and then starts the compressor.
A vehicle air conditioning device of the invention of claim 4
includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in the bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber, and the vehicle air conditioning device is
characterized in that in the second operation mode, the control
device monitors a difference in pressure between an inlet side of
the first opening/closing valve and an outlet side thereof, and
opens the first opening/closing valve when the pressure on the
outlet side of the first opening/closing valve is higher than the
pressure on the inlet side thereof.
The vehicle air conditioning device of the invention of claim 5 is
characterized in that each of the above inventions includes an
auxiliary heating device to heat the air to be supplied from the
air flow passage to the vehicle interior, the first operation mode
includes any one, any combination or all of a heating mode to let
the refrigerant discharged from the compressor radiate heat in the
radiator, decompress the refrigerant from which the heat has been
radiated, through the outdoor expansion valve, and then let the
refrigerant absorb heat in the outdoor heat exchanger, a
dehumidifying and cooling mode to send the refrigerant discharged
from the compressor through the radiator to the outdoor heat
exchanger, let the refrigerant radiate heat in the radiator and the
outdoor heat exchanger, decompress the refrigerant from which the
heat has been radiated, and then let the refrigerant absorb heat in
the heat absorber, and a cooling mode to send the refrigerant
discharged from the compressor through the radiator to the outdoor
heat exchanger, let the refrigerant radiate heat in the outdoor
heat exchanger, decompress the refrigerant from which the heat has
been radiated, and then let the refrigerant absorb heat in the heat
absorber, and the second operation mode includes either one or all
of a dehumidifying and heating mode to send the refrigerant
discharged from the compressor through the bypass pipe to the
outdoor heat exchanger, let the refrigerant radiate heat,
decompress the refrigerant from which the heat has been radiated,
let the refrigerant absorb heat in the heat absorber, and generate
heat in the auxiliary heating device, and a maximum cooling mode to
send the refrigerant discharged from the compressor through the
bypass pipe to the outdoor heat exchanger, let the refrigerant
radiate heat, decompress the refrigerant from which the heat has
been radiated, and then let the refrigerant absorb heat in the heat
absorber.
The vehicle air conditioning device of the invention of claim 6 is
characterized in that in the above invention, the first operation
mode is the heating mode or the dehumidifying and cooling mode, and
the second operation mode is the dehumidifying and heating
mode.
Advantageous Effect of the Invention
According to the invention of claim 1, a vehicle air conditioning
device includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in this bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber. In the vehicle air conditioning device, after the
first operation mode is shifted to the second operation mode, the
control device opens the first opening/closing valve at a timing to
stop the compressor. Consequently, after the mode is shifted to the
second operation mode to close the first opening/closing valve and
open the second opening/closing valve and the compressor is then
stopped, it is possible to eliminate the disadvantage that a
reverse pressure is applied to the first opening/closing valve. In
consequence, it is possible to previously eliminate or inhibit the
disadvantage that hunting occurs in the first opening/closing valve
to generate noise or the problem that durability of the first
opening/closing valve deteriorates.
In this case, when the number of times to open the first
opening/closing valve by the control device is limited as in the
invention of claim 2, it is possible to previously avoid
unnecessary opening/closing of the first opening/closing valve.
According to the invention of claim 3, a vehicle air conditioning
device includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in this bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber. In the vehicle air conditioning device, when
shifting from the first operation mode to the second operation
mode, the control device stops the compressor prior to execution of
control to each of the closing of the first opening/closing valve,
the opening of the second opening/closing valve and the shutoff of
the outdoor expansion valve, then closes the first opening/closing
valve, opens the second opening/closing valve, shuts off the
outdoor expansion valve, and then starts the compressor.
Consequently, when the first opening/closing valve is closed and
the outdoor expansion valve is shut off, the compressor is stopped,
and a pressure in a circuit including the radiator and extending
from the first opening/closing valve to the outdoor expansion valve
can be lowered. In consequence, when the mode is shifted to the
second operation mode to close the first opening/closing valve and
open the second opening/closing valve, it is possible to eliminate
or inhibit the disadvantage that a reverse pressure is applied to
the first opening/closing valve, and it is possible to previously
eliminate or inhibit the disadvantage that hunting occurs in the
first opening/closing valve to generate noise or the problem that
durability of the first opening/closing valve deteriorates.
According to the invention of claim 4, a vehicle air conditioning
device includes a compressor to compress a refrigerant, an air flow
passage through which air to be supplied to a vehicle interior
flows, a radiator to let the refrigerant radiate heat, thereby
heating the air to be supplied from the air flow passage to the
vehicle interior, a heat absorber to let the refrigerant absorb
heat, thereby cooling the air to be supplied from the air flow
passage to the vehicle interior, an outdoor heat exchanger disposed
outside the vehicle interior, an outdoor expansion valve to
decompress the refrigerant flowing out from the radiator and
flowing into the outdoor heat exchanger, a first opening/closing
valve disposed between a discharge side of the compressor and an
inlet side of the radiator, a bypass pipe which branches on an
upstream side of this first opening/closing valve and bypasses the
radiator and the outdoor expansion valve to send, to the outdoor
heat exchanger, the refrigerant discharged from the compressor, a
second opening/closing valve disposed in this bypass pipe, and a
control device, so that this control device switches between and
executes a first operation mode to open the first opening/closing
valve, close the second opening/closing valve, thereby send the
refrigerant discharged from the compressor to the radiator, and
send the refrigerant flowing out from this radiator through the
outdoor expansion valve to the outdoor heat exchanger, and a second
operation mode to shut off the outdoor expansion valve, close the
first opening/closing valve, open the second opening/closing valve,
thereby send the refrigerant discharged from the compressor through
the bypass pipe to the outdoor heat exchanger, and send the
refrigerant flowing out from this outdoor heat exchanger to the
heat absorber. In the vehicle air conditioning device, in the
second operation mode, the control device monitors a difference in
pressure between an inlet side of the first opening/closing valve
and an outlet side thereof, and opens the first opening/closing
valve when the pressure on the outlet side of this first
opening/closing valve is higher than the pressure on the inlet side
thereof. Therefore, when the mode is shifted to the second
operation mode to close the first opening/closing valve and open
the second opening/closing valve, it is possible to rapidly
eliminate a situation where a reverse pressure is applied to the
first opening/closing valve. Consequently, it is possible to
inhibit or previously eliminate the disadvantage that hunting
occurs in the first opening/closing valve to generate noise or the
problem that durability of the first opening/closing valve
deteriorates.
Here, as in the invention of claim 5, the vehicle air conditioning
device includes an auxiliary heating device to heat the air to be
supplied from the air flow passage to the vehicle interior, the
first operation mode includes any one, any combination or all of a
heating mode to let the refrigerant discharged from the compressor
radiate heat in the radiator, decompress the refrigerant from which
the heat has been radiated, through the outdoor expansion valve,
and then let the refrigerant absorb heat in the outdoor heat
exchanger, a dehumidifying and cooling mode to send the refrigerant
discharged from the compressor through the radiator to the outdoor
heat exchanger, let the refrigerant radiate heat in the radiator
and the outdoor heat exchanger, decompress the refrigerant from
which the heat has been radiated, and then let the refrigerant
absorb heat in the heat absorber, and a cooling mode to send the
refrigerant discharged from the compressor through the radiator to
the outdoor heat exchanger, let the refrigerant radiate heat in the
outdoor heat exchanger, decompress the refrigerant from which the
heat has been radiated, and then let the refrigerant absorb heat in
the heat absorber, and the second operation mode includes either
one or all of a dehumidifying and heating mode to send the
refrigerant discharged from the compressor through the bypass pipe
to the outdoor heat exchanger, let the refrigerant radiate heat,
decompress the refrigerant from which the heat has been radiated,
let the refrigerant absorb heat in the heat absorber, and generate
heat in the auxiliary heating device, and a maximum cooling mode to
send the refrigerant discharged from the compressor through the
bypass pipe to the outdoor heat exchanger, let the refrigerant
radiate heat, decompress the refrigerant from which the heat has
been radiated, and then let the refrigerant absorb heat in the heat
absorber. At this time, as in the invention of claim 6, the first
operation mode is the heating mode or the dehumidifying and cooling
mode, and the second operation mode is the dehumidifying and
heating mode. Consequently, in the dehumidifying and heating mode
often shifted from the heating mode or the dehumidifying and
cooling mode, the heat is generated in the auxiliary heating device
after the shift, and hence evaporation of the refrigerant in the
radiator is promoted.
In consequence, when the mode is shifted to the dehumidifying and
heating mode, the refrigerant rapidly flows out from the radiator
while the first opening/closing valve or the outdoor expansion
valve is opened as in the above respective inventions.
Consequently, it is possible to decrease a level of the reverse
pressure applied to the first opening/closing valve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a constitutional view of a vehicle air conditioning
device of an embodiment to which the present invention is applied
(a heating mode, a dehumidifying and heating mode, a dehumidifying
and cooling mode, and a cooling mode);
FIG. 2 is a block diagram of an electric circuit of a controller of
the vehicle air conditioning device of FIG. 1;
FIG. 3 is a constitutional view when the vehicle air conditioning
device of FIG. 1 is in a MAX cooling mode (the maximum cooling
mode);
FIG. 4 is a timing chart of each device to explain an example of
reverse pressure preventing control to be executed by the
controller of FIG. 2 when changing from the heating mode to the
dehumidifying and heating mode (Embodiment 1);
FIG. 5 is a timing chart of each device to explain another example
of the reverse pressure preventing control to be executed by the
controller of FIG. 2 when changing from the heating mode to the
dehumidifying and heating mode (Embodiment 2); and
FIG. 6 is a timing chart of each device to explain an example of
the reverse pressure preventing control to be executed by the
controller of FIG. 2 when changing from the dehumidifying and
cooling mode to the dehumidifying and heating mode (Embodiment
2).
MODE FOR CARRYING OUT THE INVENTION
Hereinafter, description will be made as to embodiments of the
present invention in detail with reference to the drawings.
FIG. 1 shows a constitutional view of a vehicle air conditioning
device 1 of one embodiment of the present invention. A vehicle of
the embodiment to which the present invention is applied is an
electric vehicle (EV) in which an engine (an internal combustion
engine) is not mounted, and runs with an electric motor for running
which is driven by power charged in a battery (which is not shown
in the drawing), and the vehicle air conditioning device 1 of the
present invention is also driven by the power of the battery.
Specifically, in the electric vehicle which is not capable of
performing heating by engine waste heat, the vehicle air
conditioning device 1 of the embodiment performs a heating mode by
a heat pump operation in which a refrigerant circuit is used, and
furthermore, the conditioning device selectively executes
respective operation modes of a dehumidifying and heating mode, a
dehumidifying and cooling mode, a cooling mode, and a MAX cooling
mode (the maximum cooling mode).
It is to be noted that the vehicle is not limited to the electric
vehicle, and the present invention is also effective for a
so-called hybrid car in which the engine is used together with the
electric motor for running. Furthermore, needless to say, the
present invention is also applicable to a normal car which runs
with the engine. Additionally, the above heating mode, the
dehumidifying and cooling mode and the cooling mode are included in
a first operation mode of the present invention, and the
dehumidifying and heating mode and the MAX cooling mode are
included in a second operation mode of the present invention.
The vehicle air conditioning device 1 of the embodiment performs
air conditioning (heating, cooling, dehumidifying, and ventilation)
of a vehicle interior of the electric vehicle, and there are
successively connected, by a refrigerant pipe 13, an electric type
of compressor 2 to compress a refrigerant, a radiator 4 disposed in
an air flow passage 3 of an HVAC unit 10 in which vehicle interior
air passes and circulates, to send inside the high-temperature
high-pressure refrigerant discharged from the compressor 2 via a
refrigerant pipe 13G and let this refrigerant radiate heat in the
vehicle interior, an outdoor expansion valve 6 constituted of an
electric valve which decompresses and expands the refrigerant
during the heating, an outdoor heat exchanger 7 which is disposed
outside the vehicle interior and performs heat exchange between the
refrigerant and outdoor air to function as the radiator during the
cooling and to function as an evaporator during the heating, an
indoor expansion valve 8 constituted of an electric valve to
decompress and expand the refrigerant, a heat absorber 9 disposed
in the air flow passage 3 to let the refrigerant absorb heat from
interior and exterior of the vehicle during the cooling and during
the dehumidifying, an accumulator 12, and others, thereby
constituting a refrigerant circuit R.
Furthermore, this refrigerant circuit R is charged with a
predetermined amount of refrigerant and a predetermined amount of
lubricating oil. It is to be noted that an outdoor blower 15 is
provided in the outdoor heat exchanger 7. The outdoor blower 15
forcibly sends the outdoor air through the outdoor heat exchanger 7
to perform the heat exchange between the outdoor air and the
refrigerant, whereby the outdoor air passes through the outdoor
heat exchanger 7 also during stopping of the vehicle (i.e., a
velocity is 0 km/h).
Additionally, the outdoor heat exchanger 7 has a receiver drier
portion 14 and a subcooling portion 16 successively on a
refrigerant downstream side, a refrigerant pipe 13A extending out
from the outdoor heat exchanger 7 is connected to the receiver
drier portion 14 via a solenoid valve 17 to be opened during the
cooling, and a refrigerant pipe 13B on an outlet side of the
subcooling portion 16 is connected to an inlet side of the heat
absorber 9 via the indoor expansion valve 8. It is to be noted that
the receiver drier portion 14 and the subcooling portion 16
structurally constitute a part of the outdoor heat exchanger 7.
In addition, the refrigerant pipe 13B between the subcooling
portion 16 and the indoor expansion valve 8 is disposed in a heat
exchange relation with a refrigerant pipe 13C on an outlet side of
the heat absorber 9, and both the pipes constitute an internal heat
exchanger 19. In consequence, the refrigerant flowing into the
indoor expansion valve 8 through the refrigerant pipe 13B is cooled
(subcooled) by the low-temperature refrigerant flowing out from the
heat absorber 9.
Furthermore, the refrigerant pipe 13A extending out from the
outdoor heat exchanger 7 branches to a refrigerant pipe 13D, and
this branching refrigerant pipe 13D communicates and connects with
the refrigerant pipe 13C on a downstream side of the internal heat
exchanger 19 via a solenoid valve 21 to be opened during the
heating. The refrigerant pipe 13C is connected to the accumulator
12, and the accumulator 12 is connected to a refrigerant suction
side of the compressor 2. Additionally, a refrigerant pipe 13E on
an outlet side of the radiator 4 is connected to an inlet side of
the outdoor heat exchanger 7 via the outdoor expansion valve 6.
In addition, a solenoid valve 30 (a first opening/closing valve in
the present application, which is the solenoid valve for reheating)
to be closed during the dehumidifying and heating and MAX cooling
described later is disposed in the refrigerant pipe 13G between a
discharge side of the compressor 2 and an inlet side of the
radiator 4. In this case, the refrigerant pipe 13G branches to a
bypass pipe 35 on an upstream side of the solenoid valve 30, and in
this bypass pipe 35, there is provided a solenoid valve 40 (a
second opening/closing valve in the present application, which is
the solenoid valve for bypass) to be opened during the
dehumidifying and heating and MAX cooling. The bypass pipe
communicates and connects with the refrigerant pipe 13E on a
downstream side of the outdoor expansion valve 6 via this solenoid
valve 40. The bypass pipe 35, the solenoid valve 30 and the
solenoid valve 40 constitute a bypass device 45.
Thus, the bypass pipe 35, the solenoid valve 30 and the solenoid
valve 40 constitute the bypass device 45, so that it is possible to
smoothly change from the dehumidifying and heating mode or the MAX
cooling mode to send, directly into the outdoor heat exchanger 7,
the refrigerant discharged from the compressor 2 as described
later, to the heating mode, the dehumidifying and cooling mode or
the cooling mode to send, into the radiator 4, the refrigerant
discharged from the compressor 2.
Furthermore, in the air flow passage 3 on an air upstream side of
the heat absorber 9, respective suction ports such as an outdoor
air suction port and an indoor air suction port are formed
(represented by a suction port 25 in FIG. 1), and in the suction
port 25, a suction changing damper 26 is disposed to change the air
to be introduced into the air flow passage 3 to indoor air which is
air of the vehicle interior (an indoor air circulating mode) and
outdoor air which is air outside the vehicle interior (an outdoor
air introducing mode). Furthermore, on an air downstream side of
the suction changing damper 26, an indoor blower (a blower fan) 27
is disposed to supply the introduced indoor or outdoor air to the
air flow passage 3.
Additionally, in FIG. 1, reference numeral 23 denotes an auxiliary
heater as an auxiliary heating device disposed in the vehicle air
conditioning device 1 of the embodiment. The auxiliary heater 23 of
the embodiment is constituted of a PTC heater which is an electric
heater, and disposed in the air flow passage 3 on an air upstream
side of the radiator 4 to the flow of the air in the air flow
passage 3. Then, when the auxiliary heater 23 is energized to
generate heat, the air in the air flow passage 3 which flows into
the radiator 4 through the heat absorber 9 is heated. That is, the
auxiliary heater 23 becomes a so-called heater core to perform or
complement the heating of the vehicle interior.
Furthermore, in the air flow passage 3 on an air upstream side of
the auxiliary heater 23, an air mix damper 28 is disposed to adjust
a degree at which the air (the indoor or outdoor air) in the air
flow passage 3, flowing into the air flow passage 3 and passed
through the heat absorber 9, passes through the auxiliary heater 23
and the radiator 4. Further in the air flow passage 3 on an air
downstream side of the radiator 4, there is formed each outlet
(represented by an outlet 29 in FIG. 1) of foot, vent or defroster,
and in the outlet 29, an outlet changing damper 31 is disposed to
execute changing control of blowing of the air from each outlet
mentioned above.
Next, in FIG. 2, reference numeral 32 denotes a controller (ECU) as
a control device constituted of a microcomputer which is an example
of a computer including a processor, and an input of the controller
32 is connected to respective outputs of an outdoor air temperature
sensor 33 which detects an outdoor air temperature (Tam) of the
vehicle, an outdoor air humidity sensor 34 which detects an outdoor
air humidity, an HVAC suction temperature sensor 36 which detects a
temperature of the air to be sucked from the suction port 25 to the
air flow passage 3, an indoor air temperature sensor 37 which
detects a temperature of the air of the vehicle interior (the
indoor air), an indoor air humidity sensor 38 which detects a
humidity of the air of the vehicle interior, an indoor air CO.sub.2
concentration sensor 39 which detects a carbon dioxide
concentration of the vehicle interior, an outlet temperature sensor
41 which detects a temperature of the air to be blown out from the
outlet 29 to the vehicle interior, a discharge pressure sensor 42
which detects a pressure (a discharge pressure Pd) of the
refrigerant discharged from the compressor 2, a discharge
temperature sensor 43 which detects a temperature of the
refrigerant discharged from the compressor 2, a suction pressure
sensor 44 which detects a pressure of the refrigerant to be sucked
into the compressor 2, a suction temperature sensor 55 which
detects a temperature of the refrigerant to be sucked into the
compressor 2, a radiator temperature sensor 46 which detects a
temperature of the radiator 4 (the temperature of the air passed
through the radiator 4 or the temperature of the radiator 4 itself:
a radiator temperature TH), a radiator pressure sensor 47 which
detects a refrigerant pressure of the radiator 4 (the pressure of
the refrigerant in the radiator 4 or immediately after the
refrigerant flows out from the radiator 4: a radiator pressure
PCI), a heat absorber temperature sensor 48 which detects a
temperature of the heat absorber 9 (the temperature of the air
passed through the heat absorber 9 or the temperature of the heat
absorber 9 itself: a heat absorber temperature Te), a heat absorber
pressure sensor 49 which detects a refrigerant pressure of the heat
absorber 9 (the pressure of the refrigerant in the heat absorber 9
or immediately after the refrigerant flows out from the heat
absorber 9), a solar radiation sensor 51 of, e.g., a photo sensor
system to detect a solar radiation amount into the vehicle, a
velocity sensor 52 to detect a moving speed (a velocity) of the
vehicle, an air conditioning operating portion 53 to set the
changing of a predetermined temperature or the switching between
operation modes, an outdoor heat exchanger temperature sensor 54
which detects a temperature of the outdoor heat exchanger 7 (the
temperature immediately after the refrigerant flows out from the
outdoor heat exchanger 7, or the temperature of the outdoor heat
exchanger 7 itself: an outdoor heat exchanger temperature TXO), and
an outdoor heat exchanger pressure sensor 56 which detects a
refrigerant pressure of the outdoor heat exchanger 7 (the pressure
of the refrigerant in the outdoor heat exchanger 7 or immediately
after the refrigerant flows out from the outdoor heat exchanger 7:
an outdoor heat exchanger pressure PXO). Furthermore, the input of
the controller 32 is further connected to an output of an auxiliary
heater temperature sensor 50 which detects a temperature of the
auxiliary heater 23 (the temperature immediately after the air is
heated by the auxiliary heater 23 or the temperature of the
auxiliary heater 23 itself: an auxiliary heater temperature
Tptc).
On the other hand, an output of the controller 32 is connected to
the compressor 2, the outdoor blower 15, the indoor blower (the
blower fan) 27, the suction changing damper 26, the air mix damper
28, the outlet changing damper 31, the outdoor expansion valve 6,
the indoor expansion valve 8, the auxiliary heater 23, and the
respective solenoid valves, i.e., the solenoid valve 30 (for the
reheating), the solenoid valve 17 (for the cooling), the solenoid
valve 21 (for the heating) and the solenoid valve 40 (for the
bypass). Then, the controller 32 controls these components on the
basis of the outputs of the respective sensors and the setting
input by the air conditioning operating portion 53.
Next, description will be made as to an operation of the vehicle
air conditioning device 1 of the embodiment having the above
constitution. In the embodiment, the controller 32 switches among
and executes the respective operation modes of the heating mode,
the dehumidifying and heating mode, the dehumidifying and cooling
mode, the cooling mode and the MAX cooling mode (the maximum
cooling mode). Description will initially be made as to a flow of
the refrigerant and an outline of control in each operation
mode.
(1) Heating Mode (First Operation Mode)
When the heating mode is selected by the controller 32 (an
automatic mode) or a manual operation to the air conditioning
operating portion 53 (a manual mode), the controller 32 opens the
solenoid valve 21 for the heating and closes the solenoid valve 17
for the cooling. Furthermore, the controller opens the solenoid
valve 30 for the reheating and closes the solenoid valve 40 for the
bypass.
Then, the controller operates the compressor 2 and the respective
blowers 15 and 27, and the air mix damper 28 has a state of
sending, to the auxiliary heater 23 and the radiator 4, all the air
in the air flow passage 3 that is blown out from the indoor blower
27 and passed through the heat absorber 9 as shown by a broken line
in FIG. 1. In consequence, a high-temperature high-pressure gas
refrigerant discharged from the compressor 2 flows into the
radiator 4 through the solenoid valve 30 and the refrigerant pipe
13G. The air in the air flow passage 3 passes through the radiator
4, and hence the air in the air flow passage 3 heats by the
high-temperature refrigerant in the radiator 4 (in the auxiliary
heater 23 and the radiator 4, when the auxiliary heater 23
operates), whereas the refrigerant in the radiator 4 has the heat
taken by the air and is cooled to condense and liquefy.
The refrigerant liquefied in the radiator 4 flows out from the
radiator 4 and then flows through the refrigerant pipe 13E to reach
the outdoor expansion valve 6. The refrigerant flowing into the
outdoor expansion valve 6 is decompressed therein, and then flows
into the outdoor heat exchanger 7. The refrigerant flowing into the
outdoor heat exchanger 7 evaporates, and the heat is pumped up from
the outdoor air passed by running or the outdoor blower 15. In
other words, the refrigerant circuit R functions as a heat pump.
Then, the low-temperature refrigerant flowing out from the outdoor
heat exchanger 7 flows through the refrigerant pipe 13A, the
solenoid valve 21 and the refrigerant pipe 13D, and flows from the
refrigerant pipe 13C into the accumulator 12 to perform gas-liquid
separation therein, and then the gas refrigerant is sucked into the
compressor 2, thereby repeating this circulation. That is, the
refrigerant flowing out from the outdoor heat exchanger 7 flows
through the accumulator 12 without passing the heat absorber 9.
Then, the air heated in the radiator 4 (in the auxiliary heater 23
and the radiator 4, when the auxiliary heater 23 operates) is blown
out from the outlet 29, thereby performing the heating of the
vehicle interior.
The controller 32 calculates a target radiator pressure PCO (a
target value of the radiator pressure PCI) from a target radiator
temperature TCO (a target value of the radiator temperature TH)
calculated from an after-mentioned target outlet temperature TAO,
and controls a number of revolution of the compressor 2 on the
basis of the target radiator pressure PCO and the refrigerant
pressure of the radiator 4 which is detected by the radiator
pressure sensor 47 (the radiator pressure PCI that is a high
pressure of the refrigerant circuit R). Furthermore, the controller
32 controls a valve position of the outdoor expansion valve 6 on
the basis of the temperature (the radiator temperature TH) of the
radiator 4 which is detected by the radiator temperature sensor 46
and the radiator pressure PCI detected by the radiator pressure
sensor 47, and controls a subcool degree SC of the refrigerant in
an outlet of the radiator 4. The target radiator temperature TCO is
basically TCO=TAO, but a predetermined limit of controlling is
provided.
Furthermore, in this heating mode, when a heating capability by the
radiator 4 runs short to a heating capability required for vehicle
interior air conditioning, the controller 32 controls the
energization of the auxiliary heater 23 to complement the shortage
by the heat generation of the auxiliary heater 23. In consequence,
comfortable vehicle interior heating is achieved, and frosting of
the outdoor heat exchanger 7 is inhibited. At this time, the
auxiliary heater 23 is disposed on the air upstream side of the
radiator 4, and hence the air flowing through the air flow passage
3 is passed through the auxiliary heater 23 before the radiator
4.
Here, if the auxiliary heater 23 is disposed on the air downstream
side of the radiator 4 and when the auxiliary heater 23 is
constituted of the PTC heater as in the embodiment, the temperature
of the air flowing into the auxiliary heater 23 rises due to the
radiator 4. Therefore, a resistance value of the PTC heater
increases, and a current value decreases to also decrease an amount
of heat to be generated, but the auxiliary heater 23 is disposed on
the air upstream side of the radiator 4, so that it is possible to
sufficiently exert a capability of the auxiliary heater 23
constituted of the PTC heater as in the embodiment.
(2) Dehumidifying and Heating Mode (Second Operation Mode)
Next, in the dehumidifying and heating mode, the controller 32
opens the solenoid valve 17 and closes the solenoid valve 21.
Furthermore, the controller closes the solenoid valve 30, opens the
solenoid valve 40, and adjusts the valve position of the outdoor
expansion valve 6 to a shutoff position. Then, the controller
operates the compressor 2 and the respective blowers 15 and 27. As
shown by the broken line in FIG. 1, the air mix damper 28 achieves
a state of sending, to the auxiliary heater 23 and the radiator 4,
all the air in the air flow passage 3 that is blown out from the
indoor blower 27 and passed through the heat absorber 9.
In consequence, the high-temperature high-pressure gas refrigerant
discharged from the compressor 2 to the refrigerant pipe 13G flows
into the bypass pipe 35 without flowing toward the radiator 4, and
flows through the solenoid valve 40 to reach the refrigerant pipe
13E on the downstream side of the outdoor expansion valve 6. At
this time, the outdoor expansion valve 6 is shut off, and hence the
refrigerant flows into the outdoor heat exchanger 7. The
refrigerant flowing into the outdoor heat exchanger 7 is cooled by
running therein or the outdoor air passed through the outdoor
blower 15, to condense. The refrigerant flowing out from the
outdoor heat exchanger 7 flows from the refrigerant pipe 13A
through the solenoid valve 17 successively into the receiver drier
portion 14 and the subcooling portion 16. Here, the refrigerant is
subcooled.
The refrigerant flowing out from the subcooling portion 16 of the
outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows
through the internal heat exchanger 19 to reach the indoor
expansion valve 8. In the indoor expansion valve 8, the refrigerant
is decompressed, and then flows into the heat absorber 9 to
evaporate. By a heat absorbing operation at this time, the air
blown out from the indoor blower 27 is cooled, and water in the air
coagulates to adhere to the heat absorber 9. Therefore, the air in
the air flow passage 3 is cooled and dehumidified. The refrigerant
evaporated in the heat absorber 9 flows through the internal heat
exchanger 19 and the refrigerant pipe 13C to reach the accumulator
12, and flows therethrough to be sucked into the compressor 2,
thereby repeating the circulation.
At this time, the valve position of the outdoor expansion valve 6
is adjusted to the shutoff position, so that it is possible to
inhibit or prevent the disadvantage that the refrigerant discharged
from the compressor 2 flows from the outdoor expansion valve 6 back
into the radiator 4. Consequently, it is possible to inhibit or
eliminate decrease of an amount of the refrigerant to be
circulated, thereby acquiring an air conditioning capability.
Furthermore, in this dehumidifying and heating mode, the controller
32 energizes the auxiliary heater 23 to generate heat.
Consequently, the air cooled and dehumidified in the heat absorber
9 is further heated in a process of passing the auxiliary heater
23, and hence a temperature rises, thereby performing the
dehumidifying and heating of the vehicle interior.
The controller 32 controls the number of revolution of the
compressor 2 on the basis of the temperature (the heat absorber
temperature Te) of the heat absorber 9 which is detected by the
heat absorber temperature sensor 48 and a target heat absorber
temperature TEO that is a target value of the heat absorber
temperature, and the controller controls the energization (the heat
generation) of the auxiliary heater 23 on the basis of the
auxiliary heater temperature Tptc detected by the auxiliary heater
temperature sensor 50 and the above-mentioned target radiator
temperature TCO. Consequently, the drop of the temperature of the
air blown out from the outlet 29 to the vehicle interior is
accurately prevented by the heating of the auxiliary heater 23,
while appropriately performing the cooling and dehumidifying of the
air in the heat absorber 9.
In consequence, the temperature of the air blown out to the vehicle
interior can be controlled at an appropriate heating temperature
while dehumidifying the air, and it is possible to achieve
comfortable and efficient dehumidifying and heating of the vehicle
interior. Furthermore, as described above, in the dehumidifying and
heating mode, the air mix damper 28 has a state of sending, through
the auxiliary heater 23 and the radiator 4, all the air in the air
flow passage 3. Therefore, the air passed through the heat absorber
9 is efficiently heated by the auxiliary heater 23, thereby
improving energy saving properties, and controllability of the air
conditioning for the dehumidifying and heating can improve.
It is to be noted that the auxiliary heater 23 is disposed on the
air upstream side of the radiator 4, and hence the air heated by
the auxiliary heater 23 passes through the radiator 4. However, in
this dehumidifying and heating mode, the refrigerant does not flow
through the radiator 4, and hence it is possible to eliminate the
disadvantage that heat is absorbed, by the radiator 4, from the air
heated by the auxiliary heater 23. Specifically, it is possible to
inhibit the temperature drop of the air blown out to the vehicle
interior by the radiator 4, and a coefficient of performance (COP)
improves.
(3) Dehumidifying and Cooling Mode (First Operation Mode)
Next, in the dehumidifying and cooling mode, the controller 32
opens the solenoid valve 17 and closes the solenoid valve 21. The
controller also opens the solenoid valve 30 and closes the solenoid
valve 40. Then, the controller operates the compressor 2 and the
respective blowers 15 and 27, and the air mix damper 28 has the
state of sending, through the auxiliary heater 23 and the radiator
4, all the air in the air flow passage 3 that is blown out from the
indoor blower 27 and passed through the heat absorber 9 as shown by
the broken line in FIG. 1. Consequently, the high-temperature
high-pressure gas refrigerant discharged from the compressor 2
flows through the solenoid valve 30 and flows from the refrigerant
pipe 13G into the radiator 4. The air in the air flow passage 3
passes through the radiator 4, and hence the air in the air flow
passage 3 is heated by the high-temperature refrigerant in the
radiator 4, whereas the refrigerant in the radiator 4 has the heat
taken by the air and is cooled to condense and liquefy.
The refrigerant flowing out from the radiator 4 flows through the
refrigerant pipe 13E to reach the outdoor expansion valve 6, and
flows through the outdoor expansion valve 6 controlled to slightly
open, to flow into the outdoor heat exchanger 7. The refrigerant
flowing into the outdoor heat exchanger 7 is cooled by the running
therein or the outdoor air passed through the outdoor blower 15, to
condense. The refrigerant flowing out from the outdoor heat
exchanger 7 flows from the refrigerant pipe 13A through the
solenoid valve 17 to successively flow into the receiver drier
portion 14 and the subcooling portion 16. Here, the refrigerant is
subcooled.
The refrigerant flowing out from the subcooling portion 16 of the
outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows
through the internal heat exchanger 19 to reach the indoor
expansion valve 8. The refrigerant is decompressed in the indoor
expansion valve 8 and then flows into the heat absorber 9 to
evaporate. The water in the air blown out from the indoor blower 27
coagulates to adhere to the heat absorber 9 by the heat absorbing
operation at this time, and hence the air is cooled and
dehumidified.
The refrigerant evaporated in the heat absorber 9 flows through the
internal heat exchanger 19 and the refrigerant pipe 13C to reach
the accumulator 12, and flows therethrough to be sucked into the
compressor 2, thereby repeating this circulation. In this
dehumidifying and cooling mode, the controller 32 does not energize
the auxiliary heater 23, and hence the air cooled and dehumidified
in the heat absorber 9 is reheated in the process of passing the
radiator 4 (a radiation capability is lower than that during the
heating). Consequently, the dehumidifying and cooling of the
vehicle interior is performed.
The controller 32 controls the number of revolution of the
compressor 2 on the basis of the temperature of the heat absorber 9
(the heat absorber temperature Te) which is detected by the heat
absorber temperature sensor 48, also controls the valve position of
the outdoor expansion valve 6 on the basis of the above-mentioned
high pressure of the refrigerant circuit R, and controls the
refrigerant pressure of the radiator 4 (the radiator pressure
PCI).
(4) Cooling Mode (First Operation Mode)
Next, in the cooling mode, the controller 32 adjusts the valve
position of the outdoor expansion valve 6 to a fully opened
position in the above state of the dehumidifying and cooling mode.
It is to be noted that the controller 32 controls the air mix
damper 28 to adjust a ratio at which the air in the air flow
passage 3, blown out from the indoor blower 27 and passed through
the heat absorber 9, passes through the auxiliary heater 23 and the
radiator 4 as shown by a solid line in FIG. 1. Furthermore, the
controller 32 does not energize the auxiliary heater 23.
In consequence, the high-temperature high-pressure gas refrigerant
discharged from the compressor 2 flows through the solenoid valve
30 and flows from the refrigerant pipe 13G into the radiator 4, and
the refrigerant flowing out from the radiator 4 flows through the
refrigerant pipe 13E to reach the outdoor expansion valve 6. At
this time, the outdoor expansion valve 6 is fully opened, and hence
the refrigerant passes the outdoor expansion valve to flow into the
outdoor heat exchanger 7 as it is, in which the refrigerant is
cooled by the running therein or the outdoor air passed through the
outdoor blower 15, to condense and liquefy. The refrigerant flowing
out from the outdoor heat exchanger 7 flows from the refrigerant
pipe 13A through the solenoid valve 17 to successively flow into
the receiver drier portion 14 and the subcooling portion 16. Here,
the refrigerant is subcooled.
The refrigerant flowing out from the subcooling portion 16 of the
outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows
through the internal heat exchanger 19 to reach the indoor
expansion valve 8. The refrigerant is decompressed in the indoor
expansion valve 8 and then flows into the heat absorber 9 to
evaporate. By the heat absorbing operation at this time, the air
blown out from the indoor blower 27 is cooled. Furthermore, the
water in the air coagulates to adhere to the heat absorber 9.
The refrigerant evaporated in the heat absorber 9 flows through the
internal heat exchanger 19 and the refrigerant pipe 13C to reach
the accumulator 12, and flows therethrough to be sucked into the
compressor 2, thereby repeating this circulation. The air cooled
and dehumidified in the heat absorber 9 is blown out from the
outlet 29 to the vehicle interior (a part of the air passes the
radiator 4 to perform heat exchange), thereby performing the
cooling of the vehicle interior. In this cooling mode, the
controller 32 also controls the number of revolution of the
compressor 2 on the basis of the temperature of the heat absorber 9
(the heat absorber temperature Te) which is detected by the heat
absorber temperature sensor 48 and the target heat absorber
temperature TEO that is the target value of the heat absorber
temperature.
(5) MAX Cooling Mode (Maximum Cooling Mode: Second Operation
Mode)
Next, in the MAX cooling mode that is the maximum cooling mode, the
controller 32 opens the solenoid valve 17 and closes the solenoid
valve 21. The controller also closes the solenoid valve 30, opens
the solenoid valve 40, and adjusts the valve position of the
outdoor expansion valve 6 to the shutoff position. Then, the
controller operates the compressor 2 and the respective blowers 15
and 27, and the air mix damper 28 has a state where the air in the
air flow passage 3 does not pass through the auxiliary heater 23
and the radiator 4 as shown in FIG. 3. However, even when the air
slightly passes, there are not any problems. Furthermore, the
controller 32 does not energize the auxiliary heater 23.
In consequence, the high-temperature high-pressure gas refrigerant
discharged from the compressor 2 to the refrigerant pipe 13G flows
into the bypass pipe 35 without flowing toward the radiator 4, and
flows through the solenoid valve 40 to reach the refrigerant pipe
13E on the downstream side of the outdoor expansion valve 6. At
this time, the outdoor expansion valve 6 is shut off, and hence the
refrigerant flows into the outdoor heat exchanger 7. The
refrigerant flowing into the outdoor heat exchanger 7 is cooled by
running therein or the outdoor air passed through the outdoor
blower 15, to condense. The refrigerant flowing out from the
outdoor heat exchanger 7 flows from the refrigerant pipe 13A
through the solenoid valve 17 successively into the receiver drier
portion 14 and the subcooling portion 16. Here, the refrigerant is
subcooled.
The refrigerant flowing out from the subcooling portion 16 of the
outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows
through the internal heat exchanger 19 to reach the indoor
expansion valve 8. In the indoor expansion valve 8, the refrigerant
is decompressed and then flows into the heat absorber 9 to
evaporate. By the heat absorbing operation at this time, the air
blown out from the indoor blower 27 is cooled. Furthermore, the
water in the air coagulates to adhere to the heat absorber 9, and
hence the air in the air flow passage 3 is dehumidified. The
refrigerant evaporated in the heat absorber 9 flows through the
internal heat exchanger 19 and the refrigerant pipe 13C to reach
the accumulator 12, and flows therethrough to be sucked into the
compressor 2, thereby repeating the circulation. At this time, the
outdoor expansion valve 6 is shut off, so that it is similarly
possible to inhibit or prevent the disadvantage that the
refrigerant discharged from the compressor 2 flows from the outdoor
expansion valve 6 back into the radiator 4. Consequently, it is
possible to inhibit or eliminate the decrease of the amount of the
refrigerant to be circulated, and it is possible to acquire the air
conditioning capability.
Here, in the above-mentioned cooling mode, the high-temperature
refrigerant flows through the radiator 4, and hence direct heat
conduction from the radiator 4 to the HVAC unit 10 considerably
occurs, but the refrigerant does not flow through the radiator 4 in
this MAX cooling mode. Therefore, the air from the heat absorber 9
in the air flow passage 3 is not heated by heat transmitted from
the radiator 4 to the HVAC unit 10. Consequently, powerful cooling
of the vehicle interior is performed, and especially under an
environment where the outdoor air temperature Tam is high, the
vehicle interior can rapidly be cooled to achieve the comfortable
air conditioning of the vehicle interior. Also in this MAX cooling
mode, the controller 32 controls the number of revolution of the
compressor 2 on the basis of the temperature of the heat absorber 9
(the heat absorber temperature Te) which is detected by the heat
absorber temperature sensor 48 and the target heat absorber
temperature TEO that is the target value of the heat absorber
temperature.
(6) Switching Between Operation Modes
The air circulated in the air flow passage 3 is subjected to the
cooling from the heat absorber 9 and a heating operation from the
radiator 4 (and the auxiliary heater 23) (adjusted by the air mix
damper 28) in the above respective operation modes, and the air is
blown out from the outlet 29 into the vehicle interior. The
controller 32 calculates the target outlet temperature TAO on the
basis of the outdoor air temperature Tam detected by the outdoor
air temperature sensor 33, the temperature of the vehicle interior
which is detected by the indoor air temperature sensor 37, the
blower voltage, the solar radiation amount detected by the solar
radiation sensor 51 and others, and the target vehicle interior
temperature (the predetermined temperature) set in the air
conditioning operating portion 53. The controller switches among
the respective operation modes, and controls the temperature of the
air blown out from the outlet 29 at this target outlet temperature
TAO.
In this case, the controller 32 changes the operation mode from the
heating mode to the dehumidifying and heating mode, from the
dehumidifying and heating mode to the dehumidifying and cooling
mode, from the dehumidifying and cooling mode to the cooling mode,
from the cooling mode to the MAX cooling mode, from this MAX
cooling mode to the cooling mode, from the cooling mode to the
dehumidifying and cooling mode, from the dehumidifying and cooling
mode to the dehumidifying and heating mode, and from the
dehumidifying and heating mode to the heating mode on the basis of
parameters such as the outdoor air temperature Tam, the humidity of
the vehicle interior, the target outlet temperature TAO, the
radiator temperature TH, the target radiator temperature TCO, the
heat absorber temperature Te, the target heat absorber temperature
TEO, and presence/absence of requirement for the dehumidifying of
the vehicle interior. Furthermore, there is also a case where the
controller changes from the heating mode to the dehumidifying and
cooling mode or the cooling mode, and from the dehumidifying and
cooling mode or the cooling mode to the heating mode. In the
embodiment, the controller changes the respective operation modes
as described above, to accurately switch among the heating mode,
the dehumidifying and heating mode, the dehumidifying and cooling
mode, the cooling mode and the MAX cooling mode in accordance with
environment conditions or necessity for the dehumidifying, thereby
achieving comfortable and efficient air conditioning of the vehicle
interior.
Embodiment 1
(7) Bumping Preventing Control, Refrigerant Scavenging Operation
and Reverse Pressure Preventing Control (No. 1) at Change from
Heating Mode to Dehumidifying and Heating Mode
Next, description will be made as to bumping preventing control to
be executed by the controller 32 when changing from the above
heating mode (the first operation mode) to the dehumidifying and
heating mode (the second operation mode), a refrigerant scavenging
operation, and reverse pressure preventing control after shift,
with reference to FIG. 4.
(7-1) Bumping Preventing Control
Here, as described above, the refrigerant and oil flowing out from
the compressor 2 through the refrigerant circuit R flow into the
accumulator 12 when the compressor 2 is stopped, their liquid part
is accumulated in the accumulator 12, and the oil having a smaller
specific weight forms a layer on the liquid refrigerant, thereby
bringing about a state of being closed with a lid. Particularly, in
the heating mode, there increase amounts of the liquid refrigerant
and oil which flow out from the outdoor heat exchanger 7 through
the solenoid valve 21 into the accumulator 12 and are accumulated
therein.
In this state, when the operation mode changes from the heating
mode to the dehumidifying and heating mode, the refrigerant flowing
out from the outdoor heat exchanger 7 flows from the solenoid valve
17 in a direction of the indoor expansion valve 8. Then, the
compressor 2 sucks the refrigerant in the accumulator 12, and hence
a pressure in the accumulator 12 rapidly drops. Then, bumping
occurs where the refrigerant below the oil boils and vaporizes
without stopping, and intensely breaks through the upper oil layer,
thereby causing excessive liquid return to the compressor 2 and
generating sound (noise).
To eliminate such problem, when changing from the heating mode to
the dehumidifying and heating mode, the controller 32 executes the
bumping preventing control which will be described below.
Description will be made as to an example of the bumping preventing
control to be executed by the controller 32 when changing the
operation mode of the vehicle air conditioning device 1 from the
above-mentioned heating mode (the first operation mode) to the
dehumidifying and heating mode (the second operation mode), with
reference to FIG. 4. A timing chart of FIG. 4 shows a number of
revolution NC of the compressor 2, the valve position of the
outdoor expansion valve 6, and states of the solenoid valve 40
(bypass), the solenoid valve 30 (reheating), the solenoid valve 17
(cooling) and the solenoid valve 21 (heating), when shifting from
the heating mode to the dehumidifying and heating mode.
The controller 32 reduces and maintains the valve position of the
outdoor expansion valve 6 for a predetermined period of time before
shifting from the heating mode to the dehumidifying and heating
mode. Furthermore, the controller maintains the number of
revolution NC of the compressor 2 which is higher than a lower
limit of an operation range for this period of time.
Thus, the valve position of the outdoor expansion valve 6 is
reduced, so that most of the refrigerant discharged from the
compressor 2 is dammed up in the radiator 4 and the refrigerant
pipe 13E between the radiator 4 and the outdoor expansion valve 6
(actually also including the pipe 13G between the solenoid valve 30
and the radiator 4) before shifting from the heating mode to the
dehumidifying and heating mode, and the subcool degree SC of the
refrigerant in the radiator 4 increases. Therefore, the refrigerant
flowing from the outdoor expansion valve 6 through the outdoor heat
exchanger 7 and the solenoid valve 21 into the accumulator 12 is
limited.
In consequence, an amount of a liquid refrigerant to be stored in
the accumulator 12 is decreased before shifting to the
dehumidifying and heating mode. Therefore, there decreases impact
of bumping which occurs when the mode shifts to the dehumidifying
and heating mode and a pressure in the accumulator 12 drops as
described later. Consequently, liquid compression in the compressor
2 and generation of noise in the accumulator 12 are effectively
eliminated or inhibited. In consequence, reliability of the vehicle
air conditioning device 1 enhances, and comfort of passengers also
effectively improves.
In this case, the controller 32 maintains a high number of
revolution NC of the compressor 2 for the predetermined period of
time before shifting to the dehumidifying and heating mode.
Consequently, it is possible to rapidly move the refrigerant in the
accumulator 12 into the radiator 4 and the refrigerant pipe 13E
between the radiator 4 and the outdoor expansion valve 6, and it is
possible to speed up the changing to the dehumidifying and heating
mode.
(7-2) Refrigerant Scavenging Operation
Furthermore, as described above, in the dehumidifying and heating
mode, the solenoid valve 30 is closed and the outdoor expansion
valve 6 is also shut off, thereby bringing about a state where any
refrigerant is not sent through the radiator 4. Consequently, when
the heating mode is changed to the dehumidifying and heating mode,
the refrigerant remaining in the radiator 4 is laid up therein for
a long time, and the amount of the refrigerant to be circulated
decreases. In particular, when the bumping preventing control is
executed as described above, the amount of the refrigerant
remaining in the radiator 4 increases.
To eliminate the problem, the controller 32 executes a refrigerant
scavenging operation when changing from the heating mode to the
dehumidifying and heating mode in the embodiment. This refrigerant
scavenging operation is executed after the above-mentioned bumping
preventing control is ended. That is, after elapse of the
predetermined period of time of the above-mentioned bumping
preventing control, the controller 32 firstly closes the solenoid
valve 21, and opens the solenoid valve 17 (the dehumidifying and
heating mode starts here). It is to be noted that at this point of
time, the solenoid valve 30 and the solenoid valve 40 are not
changed.
Then, the controller 32 starts the refrigerant scavenging
operation. In this refrigerant scavenging operation, the controller
32 enlarges (e.g., fully opens) the valve position of the outdoor
expansion valve 6 only for a predetermined period of time. This
state is similar to the state of the cooling mode. Furthermore, in
the embodiment, a number of revolution NC of the compressor 2 is
lowly maintained (e.g., the minimum number of revolution of
controlling) from the start of this refrigerant scavenging
operation.
Consequently, the refrigerant present in a region including the
radiator 4 and extending from the solenoid valve 30 to the outdoor
expansion valve 6 is expelled in a direction of the outdoor heat
exchanger 7 (scavenging). Then, after elapse of a predetermined
period of time, the controller ends the refrigerant scavenging
operation, closes the solenoid valve 30, opens the solenoid valve
40, and closes the outdoor expansion valve 6 toward its shutoff
position. Thus, the outdoor expansion valve 6 is shut off, and then
the controller 32 shifts to a state of controlling the number of
revolution of the compressor 2 in the dehumidifying and heating
mode. By such a refrigerant scavenging operation, the refrigerant
is prevented from being laid up for a long time in the radiator 4
or the like, and the amount of the refrigerant to be circulated in
the refrigerant circuit R is acquired to prevent deterioration of
an air conditioning performance.
Furthermore, the controller 32 closes the solenoid valve 30 and
opens the solenoid valve 40 after the refrigerant scavenging
operation is executed, the controller lowly maintains the number of
revolution NC of the compressor 2 until the outdoor expansion valve
6 closes after the start of the refrigerant scavenging operation,
and the controller raises the number of revolution of the
compressor 2 after the outdoor expansion valve 6 is closed.
Therefore, it is possible to decrease a difference between
pressures before and after the solenoid valve 40 (on an upstream
side and a downstream side) when opening the solenoid valve 40. In
consequence, generation of noise in opening the solenoid valve 40
is avoided.
Here, as in the embodiment, in the dehumidifying and heating mode,
the controller 32 executes the refrigerant scavenging operation to
open the outdoor expansion valve 6 and enlarge its valve position
for a predetermined period of time, when the mode is shifted to the
dehumidifying and heating mode. Consequently, a high pressure is
present in the outdoor heat exchanger 7 and a low pressure is
present in the accumulator 12. However, the solenoid valve 21 is
not opened during this refrigerant scavenging operation, and hence
any noise is not generated in the solenoid valve 21. Therefore,
according to the embodiment, it is possible to prevent or inhibit
bumping in the accumulator 12 while avoiding the generation of the
noise in the solenoid valve 21.
(7-3) Reverse Pressure Preventing Control (No. 1)
Furthermore, as described above, in the dehumidifying and heating
mode, the solenoid valve 30 is closed, the outdoor expansion valve
6 is also shut off, and the refrigerant is confined in the radiator
4 and others. In particular, if the pressure on the upstream side
of the solenoid valve 30 (on the discharge side of the compressor
2) drops during the stop of the compressor 2 immediately after the
shift to the dehumidifying and heating mode, the pressure on the
downstream side (the radiator 4 side) of the solenoid valve 30 may
become higher. In such a reverse pressure state, there is the risk
that hunting occurs in the solenoid valve 30 to generate noise and
its durability deteriorates.
To eliminate the problem, in the embodiment, after the mode is
shifted to the dehumidifying and heating mode, the controller 32
executes the reverse pressure preventing control to open the
solenoid valve 30 at a timing to stop the compressor 2. In
consequence, it is possible to eliminate the disadvantage that the
reverse pressure is applied to the solenoid valve 30 during the
stop of the compressor 2 after the mode is shifted to the
dehumidifying and heating mode to close the solenoid valve 30 and
open the solenoid valve 40, and it is possible to previously
eliminate or inhibit the disadvantage that the hunting occurs in
the solenoid valve 30 to generate noise or the problem that
durability of the solenoid valve 30 deteriorates.
However, the controller 32 limits this control to open the solenoid
valve 30, for example, until the second timing to stop the
compressor 2 after the mode is shifted to the dehumidifying and
heating mode. In consequence, unnecessary opening/closing of the
solenoid valve 30 is avoided (provided that the number of times may
be one or three or more).
Embodiment 2
(8) Differential Pressure Lowering Control, Reverse Pressure
Preventing Control (No. 2), and Bumping Preventing Control at
Change from Heating Mode to Dehumidifying and Heating Mode
Next, description will be made as to another embodiment of the
control to be executed by the controller 32 when changing from the
above heating mode (the first operation mode) to the dehumidifying
and heating mode (the second operation mode), with reference to
FIG. 5. In this embodiment, the controller 32 executes differential
pressure lowering control, reverse pressure preventing control and
bumping preventing control as shown in FIG. 5, when changing from
the heating mode to the dehumidifying and heating mode.
(8-1) Differential Pressure Lowering Control
Here, in the heating mode, the solenoid valve 40 is closed and in
the dehumidifying and heating mode, the solenoid valve 40 is
opened. However, in the heating mode, the pressure on the inlet
side of the solenoid valve 40 corresponds to the pressure on the
discharge side of the compressor 2, and is high, and the pressure
on the outlet side thereof has a low pressure state on the outlet
side of the outdoor expansion valve 6. In such a state, when the
solenoid valve 40 opens, large noise is generated. Consequently,
when the heating mode is shifted to the dehumidifying and heating
mode, the controller 32 firstly executes the differential pressure
lowering control for a predetermined period of time (T1).
Description will be made as to an example of the differential
pressure lowering control to be executed by the controller 32 when
changing the operation mode of the vehicle air conditioning device
1 from the heating mode (the first operation mode) to the
dehumidifying and heating mode (the second operation mode), with
reference to FIG. 5. A timing chart of FIG. 5 shows the number of
revolution NC of the compressor 2, the valve position of the
outdoor expansion valve 6, and states of the solenoid valve 40
(bypass), the solenoid valve 30 (reheating), the solenoid valve 17
(cooling), the solenoid valve 21 (heating) and the auxiliary heater
23, when shifting from the heating mode to the dehumidifying and
heating mode.
In the heating mode, the controller 32 executes feedforward and
feedback control of the outdoor expansion valve 6. However, the
controller opens the solenoid valve 17 in this heating mode, and
closes the solenoid valve 21 to shift to the dehumidifying and
heating mode. Afterward, the controller enlarges the valve position
of the outdoor expansion valve 6 to a large predetermined value (a
fully opened position in the embodiment) and maintains the position
for the predetermined period of time (T1), before opening the
solenoid valve 40 and closing the solenoid valve 30. Furthermore,
the number of revolution NC of the compressor 2 is maintained at a
low predetermined value for this predetermined period of time (T1).
Thus, the valve position of the outdoor expansion valve 6 is
enlarged, thereby raising the pressure on the outlet side of the
solenoid valve 40, and the number of revolution NC of the
compressor 2 is decreased, thereby lowering the pressure on the
inlet side of the solenoid valve 40. Consequently, a difference in
pressure (a differential pressure) between the inlet side of the
solenoid valve 40 and the outlet side thereof decreases. In
consequence, generation of noise in opening the solenoid valve 40
thereafter is prevented or inhibited.
(8-2) Reverse Pressure Preventing Control (No. 2)
The differential pressure lowering control for this predetermined
period of time (T1) ends, and then the controller 32 shifts to
reverse pressure preventing control. In this reverse pressure
preventing control, the controller 32 opens the solenoid valve 30,
closes the solenoid valve 40, and adjusts the valve position of the
outdoor expansion valve 6 to a fully opened position. In this
state, the compressor 2 is stopped for a predetermined period of
time (T2). Consequently, the radiator pressure PCI lowers.
Then, after elapse of this predetermined period of time (T2), the
controller closes the solenoid valve 30, opens the solenoid valve
40, closes the outdoor expansion valve 6 toward its shutoff valve
position, and finally shuts off the outdoor expansion valve (the
reverse pressure preventing control is executed up to here). The
controller then starts the compressor 2. In this way, when the
heating mode shifts to the dehumidifying and heating mode, the
controller stops the compressor 2 prior to execution of control to
each of the closing of the solenoid valve 30, the opening of the
solenoid valve 40 and the shutoff of the outdoor expansion valve 6.
Then, the controller closes the solenoid valve 30, opens the
solenoid valve 40, shuts off the outdoor expansion valve 6, and
then starts the compressor 2. Consequently, when the controller
closes the solenoid valve 30 and shuts off the outdoor expansion
valve 6, the compressor 2 is stopped, and it is possible to lower a
pressure in the refrigerant circuit R including a radiator 4 and
extending from the solenoid valve 30 to the outdoor expansion valve
6.
In consequence, when the mode is shifted to the dehumidifying and
heating mode to close the solenoid valve 30 and open the solenoid
valve 40, it is possible to eliminate or inhibit the disadvantage
that a reverse pressure is applied to the solenoid valve 30, and it
is possible to previously eliminate or inhibit the disadvantage
that the hunting occurs in the solenoid valve 30 to generate the
noise or the problem that the durability of the solenoid valve 30
deteriorates.
Furthermore, in the dehumidifying and heating mode, heat is
generated in the auxiliary heater 23 after the shift, and hence
evaporation of the refrigerant in the radiator 4 is promoted.
Consequently, after the shift to the dehumidifying and heating
mode, while the solenoid valve 30 is opened and the outdoor
expansion valve 6 is fully opened, the refrigerant rapidly flows
out from the radiator 4, and hence it is possible to lower a level
of the reverse pressure applied to the solenoid valve 30.
(8-3) Bumping Preventing Control
After this reverse pressure preventing control is executed, the
controller 32 executes the bumping preventing control. In the
bumping preventing control of this embodiment, the controller 32
starts the compressor 2, gradually increases the number of
revolution NC of the compressor so that the number finally
converges to a target value, and shifts to a control state in an
operation range of the dehumidifying and heating mode. Thus, the
controller gradually increases the number of revolution NC of the
compressor 2 instead of rapidly increasing the number, thereby
preventing rapid pressure drop in the accumulator 12 and
eliminating or inhibiting occurrence of bumping therein.
(9) Differential Pressure Lowering Control and Reverse Pressure
Preventing Control at Change from Dehumidifying and Cooling Mode to
Dehumidifying and Heating Mode
Next, description will be made as to control to be executed by the
controller 32 when changing from the above dehumidifying and
cooling mode (the first operation mode) to the dehumidifying and
heating mode (the second operation mode), with reference to FIG. 6.
In this embodiment, the controller 32 executes the differential
pressure lowering control and reverse pressure preventing control
as shown in FIG. 6, when changing from the dehumidifying and
cooling mode to the dehumidifying and heating mode.
(9-1) Differential Pressure Lowering Control
Also in the dehumidifying and cooling mode, the solenoid valve 40
is closed, and in the dehumidifying and heating mode, the solenoid
valve 40 is opened. However, in the dehumidifying and cooling mode,
the pressure on the inlet side of the solenoid valve 40 corresponds
to the pressure on the discharge side of the compressor 2, and is
high, and due to the pressure on the outlet side thereof, the
solenoid valve tends to slightly open, but has a low pressure state
on the outlet side of the outdoor expansion valve 6. When the
solenoid valve 40 is opened in such a state, noise is similarly
generated. Consequently, also when the dehumidifying and cooling
mode is shifted to the dehumidifying and heating mode, the
controller 32 firstly executes the differential pressure lowering
control for a predetermined period of time (T3).
Description will be made as to an example of the differential
pressure lowering control to be executed by the controller 32 when
changing the operation mode of the vehicle air conditioning device
1 from the dehumidifying and cooling mode (the first operation
mode) to the dehumidifying and heating mode (the second operation
mode), with reference to FIG. 6. A timing chart of FIG. 6 shows the
number of revolution NC of the compressor 2, the valve position of
the outdoor expansion valve 6, and the states of the solenoid valve
40 (bypass), the solenoid valve 30 (reheat) and the auxiliary
heater 23, when shifting from the dehumidifying and cooling mode to
the dehumidifying and heating mode.
When the dehumidifying and cooling mode is shifted to the
dehumidifying and heating mode and before the solenoid valve 40 is
opened and the solenoid valve 30 is closed, the controller 32
enlarges the valve position of the outdoor expansion valve 6 up to
a large predetermined value (a fully opened position in the
embodiment) to maintain the valve position for the predetermined
period of time (T3). Furthermore, the controller maintains the
number of revolution NC of the compressor 2 at a predetermined low
value for this predetermined period of time (T3). Thus, the valve
position of the outdoor expansion valve 6 is enlarged, thereby
increasing the pressure on the outlet side of the solenoid valve
40, and the number of revolution NC of the compressor 2 is lowered,
thereby decreasing the pressure on the inlet side of the solenoid
valve 40. Consequently, the difference in pressure (the
differential pressure) between the inlet side of the solenoid valve
40 and the outlet side thereof decreases. In consequence, the
generation of the noise in opening the solenoid valve 40 is then
prevented or inhibited.
(9-2) Reverse Pressure Prevention Control (No. 2)
When the differential pressure lowering control for the
predetermined period of time (T3) is ended, the controller 32
shifts to the reverse pressure preventing control. In this case,
according to the reverse pressure preventing control, the
controller 32 opens the solenoid valve 30, closes the solenoid
valve 40, and fully opens the outdoor expansion valve 6, and in a
fully opened position of the outdoor expansion valve, the
compressor 2 is stopped for a predetermined period of time (T4).
Consequently, the radiator pressure PCI drops.
Then, after elapse of this predetermined period of time (T4), the
controller closes the solenoid valve 30, opens the solenoid valve
40, closes the outdoor expansion valve 6 to adjust its valve
position toward a shutoff position, and finally shuts off the
outdoor expansion valve (the reverse pressure preventing control is
executed up to here). Then, the controller starts the compressor 2
and shifts to a control state in the operation range of the
dehumidifying and heating mode. Thus, when the dehumidifying and
cooling mode shifts to the dehumidifying and heating mode, the
controller stops the compressor 2 prior to execution of control to
each of the closing of the solenoid valve 30, the opening of the
solenoid valve 40 and the shutoff of the outdoor expansion valve 6.
Then, the controller closes the solenoid valve 30, opens the
solenoid valve 40, shuts off the outdoor expansion valve 6, and
then starts the compressor 2. Consequently, when the solenoid valve
30 is closed and the outdoor expansion valve 6 is shut off, the
compressor 2 is stopped, and it is possible to lower the pressure
in the refrigerant circuit R including the radiator 4 and extending
from the solenoid valve 30 to the outdoor expansion valve 6.
Consequently, when the mode is shifted to the dehumidifying and
heating mode where the solenoid valve 30 is closed and the solenoid
valve 40 is opened, it is possible to eliminate or inhibit the
disadvantage that the reverse pressure is applied to the solenoid
valve 30, and it is possible to previously eliminate or inhibit the
disadvantage that the hunting occurs in the solenoid valve 30 to
generate the noise or the problem that the durability of the
solenoid valve 30 deteriorates.
Furthermore, heat is generated in the auxiliary heater 23 when the
mode is shifted to the dehumidifying and heating mode, and hence
evaporation of the refrigerant in the radiator 4 is promoted.
Consequently, when the mode is shifted to the dehumidifying and
heating mode where the solenoid valve 30 is opened and the outdoor
expansion valve 6 is fully opened, the refrigerant rapidly flows
out from the radiator 4. In consequence, it is possible to decrease
a level of the reverse pressure applied to the solenoid valve
30.
Embodiment 3
(10) Reverse Pressure Preventing Control (No. 3) in Dehumidifying
and Heating Mode
Next, description will be made as to still another embodiment of
the reverse pressure preventing control to be executed by the
controller 32 in the dehumidifying and heating mode (the second
operation mode). In this case, the controller 32 always monitors
pressures on an inlet side and an outlet side of the solenoid valve
30 in the dehumidifying and heating mode. It is to be noted that in
this embodiment, the controller judges the pressure on the inlet
side of the solenoid valve 30 from the above-mentioned discharge
pressure Pd detected by the discharge pressure sensor 42, and
judges the pressure on the outlet side of the solenoid valve 30
from the above-mentioned radiator pressure PCI detected by the
radiator pressure sensor 47.
Then, in the embodiment, when the pressure PCI on the outlet side
of the solenoid valve 30 becomes higher than the pressure Pd on the
inlet side thereof (PCI>Pd), the controller 32 opens the
solenoid valve 30. Consequently, when the mode is shifted to the
dehumidifying and heating mode where the solenoid valve 30 is
closed and the solenoid valve 40 is opened, the reverse pressure is
applied to the solenoid valve 30, and in this situation, the
reverse pressure can rapidly be eliminated. In consequence, it is
possible to inhibit or previously eliminate the disadvantage that
the hunting occurs in the solenoid valve 30 to generate the noise
or the problem that the durability of the solenoid valve 30
deteriorates. Here, when the pressure PCI on the outlet side of the
solenoid valve 30 is less than or equal to the pressure Pd on the
inlet side thereof (PCI Pd), the controller 32 closes the solenoid
valve 30 again.
It is to be noted that in Embodiment 1 mentioned above, there has
been described the case where the heating mode (the first operation
mode) shifts to the dehumidifying and heating mode (the second
operation mode), but the present invention is not limited thereto,
and is also effective for a case where the dehumidifying and
cooling mode (the first operation mode) shifts to the dehumidifying
and heating mode (the second operation mode).
Furthermore, in the above respective embodiments, the dehumidifying
and heating mode has been adopted and described as the second
operation mode, but the present invention is not limited thereto,
and is also effective when the control of each embodiment described
above is executed after the shift to the MAX cooling mode.
Additionally, in the embodiment, the present invention is applied
to the vehicle air conditioning device 1 which switches between and
executes the heating mode, the dehumidifying and heating mode, the
dehumidifying and cooling mode, the cooling mode and the MAX
cooling mode, but the present invention is not limited thereto. The
inventions of claim 1 to claim 5 are also effective for the vehicle
air conditioning device which switches between and executes at
least one of the first operation modes (the heating mode, the
dehumidifying and cooling mode, and the cooling mode) and at least
one of the second operation modes (the dehumidifying and heating
mode and the MAX cooling mode).
However, when the first operation mode is the heating mode or the
dehumidifying and cooling mode and the second operation mode is the
dehumidifying and heating mode as in each embodiment, heat is
generated in the auxiliary heater 23 after the shift to the
dehumidifying and heating mode often shifted from the heating mode
or the dehumidifying and cooling mode. Consequently, the
evaporation of the refrigerant in the radiator 4 is promoted. In
consequence, when the mode is shifted to the dehumidifying and
heating mode where the solenoid valve 30 and the outdoor expansion
valve 6 are opened, the refrigerant rapidly flows out from the
radiator 4. In consequence, it is possible to decrease the level of
the reverse pressure applied to the solenoid valve 30.
The present invention is not limited to the changing control of the
respective operation modes described in the embodiments, and
appropriate conditions may be set by employing one, any combination
or all of parameters such as the outdoor air temperature Tam, the
humidity of the vehicle interior, the target outlet temperature
TAO, the radiator temperature TH, the target radiator temperature
TCO, the heat absorber temperature Te, the target heat absorber
temperature TEO, and the presence/absence of the requirement for
the dehumidifying of the vehicle interior, in accordance with the
capability and use environment of the vehicle air conditioning
device.
Additionally, the auxiliary heating device is not limited to the
auxiliary heater 23 described in the embodiments, and a heating
medium circulating circuit which circulates a heating medium heated
by a heater to heat air in an air flow passage, a heater core which
circulates radiator water heated by an engine or the like may be
utilized. Furthermore, the constitutions of the refrigerant circuit
R which are described in the above respective embodiments are not
limited thereto, and needless to say, the constitutions are
changeable without departing from the gist of the present
invention.
DESCRIPTION OF REFERENCE NUMERALS
1 vehicle air conditioning device 2 compressor 3 air flow passage 4
radiator 6 outdoor expansion valve 7 outdoor heat exchanger 8
indoor expansion valve 9 heat absorber 12 accumulator 17 solenoid
valve 21 solenoid valve 23 auxiliary heater (an auxiliary heating
device) 27 indoor blower (a blower fan) 28 air mix damper 30
solenoid valve (a first solenoid valve) 40 solenoid valve (a second
solenoid valve) 32 controller (a control device) 35 bypass pipe 45
bypass device R refrigerant circuit
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